Gelatinized explosive



United States Patent 3,208,890 GELATINIZED EXPLOSIVE Carl Torsten Edlundand Gustav Allan Wetterholm,

Gyttorp, Sweden, assignors to Nitroglycerin Aktiebolaget, a company ofSweden No Drawing. Filed Feb. 27, 1963, Ser. No. 261,521

Claims priority, application Sweden, Feb. 28, 1962,

5 Claims. (Cl. 149-47) The present invention generally relates to anovel explosive of the gelatinized type having improved physiologicalacceptance and a low sensitivity to impact. More specifically thepresent invention pertains to an explosive comprising anoxygen-delivering inorganic salt and an explosive oil consisting ofpropylene-glycol dinitrate or a mixture of propylene-glycol dinitratewith no more than 50 percent of nitroglycerine.

glycol dinitrate unless one or the other of these individual compoundsis especially intended) are known substances having properties whichrender them suitable as explosives.

Both compounds have been suggested as ingredients in explosive alongwith oxygen-delivering inorganic salts. Such explosives are as a rulehighly insensitive to impact. Due to being considerably under-balancedwith respect to oxygen, they have not, however, obtained any practicalimportance up to the present.

It is known that propylene-glycol dinitrate-containing highlyunderbalanced explosives are highly insensitive to impact. It is alsoknown that highly overbalanced as well as underbalanced explosives aregenerally insensitive to impact, but that the sensitivity to impact willincrease on oxygen-balancing, so that mixtures of considerablesensitivity will be obtained. It has now surprisingly been found thatpropylene-glycol dinitrate-containing explosives can be produced whichmaintain their high insensitivity to impact even after oxygen-balancing.

In comparison with explosives containing nitroglycol (the dinitrate ofethylene glycol) as an additive to nitroglycerine, our noveloxygen-balanced explosives present considerable advantages. The use ofnitroglycol is, as known, connected with physiological drawbacks. Whenadmixed with nitroglycerine, the nitroglycol will increase thevasodilatory effect on the blood veins of man which is particularlymanifested as headache and indisposition. Another reason why mixtures ofnitroglycol with nitroglycerine are physiologically disadvantageous isascribed to the poisonous effect of the nitroglycol itself. In thisconnection, reference is made to the cases of sudden collapses whichwill frequently happen among workers of explosive factories who comeinto contact with this substance, usually a couple of days after leavingwork. Pro pylene-glycol dinitrate-containing explosives are decidedlymore acceptable from a physiological viewpoint and do not possess thedisadvantages above referred to.

The better physiological acceptability of propyleneglycol dinitrate maybe explained by the fact that the substance has relatively littlesolubility in the blood of man. The solubility of the propylene-glycoldinitrates in water, as compared with nitroglycerine and nitroglycol(the dinitrate'of ethylene glycol), is evident from the following table.The values set forth relate to the solubility at 20 C.

Percent Nitroglycerine 0.18 Nitroglycol 0.63 1-,3-propylene-glycoldinitrate 0.24 1,2-propylene-glycol dinitrate 0.13

3,208,890 Patented Sept. 28, 1965 THE PRESENT INVENTION The presentinvention relates to an explosive having an improved physiologicalacceptance and a low sensitivity to impact, consisting of or containingpropylene-glycol dinitrate, and one or more inorganic oxygen-deliveringsalts. One important characterizing feature of the explosive accordingto the invention is that the oxygen-delivering inorganic salt or saltsare present in a suflicient amount to substantially oxygen-balance theexplosive.

Because the explosives according to the invention possess a combinationof high insensitivity to impact with an excellent physiologicalacceptance, they represent a valuable advance in the field ofexplosives.

A further feature of the invention is that the explosive contains 370%propylene-glycol dinitrate and 10-95% oxygen-delivering inorganic salt.

The propylene-glycol dinitrate can either be the only liquid ingredientof the explosive oil, or it can be admixed with other liquidingredients. If the explosive oil is a mixture of different substances,may contain up to about 50 percent of nitroglycerine. It is natural thatthe explosive must not contain any substantial amounts of nitro-GELATINIZING OF THE EXPLOSIVE OIL An explosive oil, consisting ofpropylene-glycol dinitrate or at least mainly of this substance, doesnot form a gel with nitrocellulose at usual temperatures. In order toattain gelatinizing, increased temperatures Will be required. In thisconnection, that, especially if subjected to alternating freezing andthawing, rgels produced at high temperatures will gradually releasetheir oil. It may be noted that amounts as high as 14 percent ofnitrocellulose have been suggested to obtain an acceptable gel.According to a further embodiment 'of the invention, this amount can bedecreased considerably if there is added to the ex-- plosive oil anagent capable of facilitating the gelatinizing (i.e., a gelatinizingaid) in an amount of 02-10 percent, preferably 0.57 percent, based onthe total weight of the explosive oil. There is thus obtained theimportant elfect that the explosive oil will gelatinize at normaltemperatures and, furthermore, the amount 'of gelatinizing agent(nitrocellulose) which is an expensive product, can be decreased withoutany essential drawbacks resulting. A fully acceptable gelatinizing ofpropyleneglycol dinitrate can be attained by less than 8 percent ofnitrocellulose in the explosive oil. Usually, only 3-5 percent isrequired to attain this result.

As gelatinizing aids may generally be mentioned hydrogen bond-formingsubstances. Such aids will be effective in proportion to their abilityto form such bonds. As examples of such substances there may bementioned:

Alc0h0ls.Aliphatic monohydric primary, secondary and tertiary alcohols,containing from 1 to 10 carbon atoms, for example methanol, ethanol,isopropylalcohol, n-propylalcohol, the butyl alcohols, the amylalcohols, n-decanol and nonyl carbinol, aliphatic polyhydric alcoholssuch as ethylene-glycol, diethylene-glycol, the propylene-glycols andglycerol;

Ketones.Aliphatic ketones such as acetone, methylit has been proved thecontent of which may be 8 percent or less.

ethyl-ketone, methylisobutyl-ketone and up to the decanones as well asthe bicyclic ketone camphor;

Esters.Esters of aliphatic alcohols with formic acid, acetic acid, andpropionic acid, for example ethyl acetate and butyl acetate, polyhydricalcohols partially esterified with acetic acid or nitric acid such asthe partial esters of ethylene-glycol, diethylene-glycol, thepropyleneglycols and glycerol with acetic aaid and nitric acid, such asmononitroglycerine, mononitroglycol and dinitroglycerine;

Eth'ers.With lower alkyls monosubstituted ethyleneglycol anddiethylene-glycol in which the lower alkyls may be methyl, ethyl, propyland butyl, such as glycolmonomethylether and glycol-monoethylether.

Other gelatinizing aids are monoand di-nitrosubstituted derivatives ofbenzene and toluene. If an explosive oil, containing propylene-glycoldinitrate, is free from nitroglycerine, the latter substance may beadded as a gelatinizing aid up to amounts of 8 percent, for example.

THE OXYGEN-DELIVERING INORGANIC SALT TABLE Oxygeitbalaneed mixtureOxygen-deliveriug-salt Percent salt Percent Ammonium nitrate NH4NO3Sodium nitrate NaNO;

Potassium chlorate K Sodium chlorate NaClO3 Potassium perchlorate KClO4Ammonium perchlorate NH4ClO4 OTHER INGREDIENTS The explosive accordingto the invention may contain high brisant explosives such as trotyl,pentyl, hexogen etc. Furthermore, it may contain usual oxygen-consumingsubstances such as saw duct, flours of different kinds and metalpowders, and usual fillers such as kieselguhr.

TYPES OF EXPLOSIVE INVOLVED The gelatinized explosives according to theinvention may be produced'in different forms, namely, as powders or inplastic or semiplastic conditions. These explosives may also contain asan ingredient finely divided metals This especially applies to powderexplosives, but also the plastic and semiplastic explosives may containlow amounts of finely divided metals.

EXAMPLES The following examples are illustrative of preferredembodiments of the present invention. It should be understood that theseexamples are not intended to limit the invention and that obviouschanges may be made by those skilled in the art without changing theessential characteristics and the basic concept of the invention.

Example 1 A plastic explosive was made up by mixing together thefollowing ingredients:

Gap test (24 mm. cartridge), mm. at 20 C. l30 Impact sensitivity testaccording to Kast, 2 kg.

fall weight, percent detonation per cm. fall height 0/60 The mixture wasprepared by first mixing together the propylene-glycol dinitrate and thenitrocellulose, whereupon the methanol was added to the mixtureobtained. Gelatinizing took place satisfactorily without heating themixture. Then the salt mixture was added and finally the wood flourtogether with the chalk.

Example 2 A plastic explosive was made up by mixing together thefollowing ingredients:

g. 1,2-propylene-glycol dinitrate 37.0 Nitrocellulose 1.4 Ethyl diglycol0.4 Ammonium nitrate 41.3 Sodium nitrate 18.85 Cork flour 1.0 Chalk 0.05

The oxygen-balance of the explosive was +40%.

The properties of the explosive were the following:

Volume weight 1.45 Gap test (25 mm. cartridge), mm. at 20 C. -180 Impactsensitivity test according to Kast, 2 kg.

fall weight, percent detonation per cm. fall weight 0/06 Example 3 Aplastic explosive was made up by mixing together the followingingredients:

g. 1,2-propylene-glycol dinitrate 37.5 Nitrocellulose 1.3 Methanol 0.4Camphor 0.4 Ammonium nitrate 41.1 Sodium nitrate 18.75 Wood fiour 0.5Chalk 0.05

The oxygen-balance of the explosive was +33%.

The properties of the explosive were the following:

Volume weight 1.49 Gap test (25 mm. cartridge), mm. at 20 C. 80-100Impact sensitivity test according to Kast, 2 kg.

fall weight, percent detonation per cm. tall weight 0/ 60 In thefollowing table, there are listed further examples for the compositionof the explosive according to the invention and an example of acomposition, containing ethylene-glycol dinitrate, given for purpose ofcomparison.

TABLE Powder Semiplastic explosive explosive with nitrowithnitrocellulose cellulose 1,2-propylene-glycoldinitrate. 6. 3 23.Dinitrotoluene 2. 0 Methylethy1ketone 0. 5 Trotyl 11. 0 Nitrocellulose0. 1 Ammonium nitrate 69. 1 Sulfur Sodium nitrate. 7. 0 Aluminiunn 2. 0Wood flour... 2. 7 Kieselguhr- 1. 1 Paraffin 0. 2

Oxygen-balance, percent +0. 6 +1. 8 Properties:

Volume weight 1. 1 1. 46 Detonation velocity, kITL/S 4. 7 2. 75 Gap test(25 mm. cartridge) mm. at

20 C 0-10 0-10 Impact sensitivy test according to Kast, by 2 kg. fallweight, percent detonation per cm. tall height 0/60 0/60 Plasticexplosives- With propylene-glycol With dinitrate ethyleneglycoldinitrate1,2-propylene-glyco1 dinitrate 37. 0 54. 0 30. 0 1,3

' 30. 0 Nitroglycerine 7. 5 2. 0 20. 0 Ethylene-glycol dinitrate 20. 0Dinitrotoluene 3. 0 3. 0 1. 0 3. 5 Nitrocellulose 1. 3 1. 3 1. 5 l. 0 1.5 Monoacetin 0. 5 2. 0 Amrnonium nitrate. 29. 55 23. 61. 0 53. 95 Sodiumnitrate 27. 6 33. 85 3. 95 Ammonium perchlorate. 40. 0 Wood flour 1.0 1. 0 3.0 1. 0 Chalk 0. 05 0. 05 0. 05 0. 05

Oxygen-balance, percent +4. 5 +4 1 4 Properties:

Volume weight 1. 5O 1. 55 1. 45 Detonatation velocity, km./s 4. 0 3. 26. 1 Gap test (25 mm.

cartridge) mm. at

C 180-200 150-200 230 Impact sensitivity test according to Kast, percentdetonation per cm. fall helght 0/60 0/60 0/60 0/60 10/30 As is evidentfrom the above examples, the novel explosive according to the presentinvention has a very low sensitivity to impact. This is especiallyapparent when comparing the fall heights of the explosives according tothe present invention (Examples 1 to 9) with what occurs to thenitroglycol-containing explosive according to Example 10. While in thelast mentioned case, the percent of detonations amounted to 10 percenteven for 300 mm. fall height, none of the nine compositions ofexplosives according to the present invention gave any detonation evenfor a fall height as high as 600 mm.

Those skilled in the chemical arts, and particularly in the art to whichthis invention pertains, will readily appreciate that many modificationsof the basic invention set forth here are possible. For example, itwould not involve invention to try closely related compounds in view ofthe present broad disclosure or in trying amounts different than thosedisclosed. All such obvious modifications would not avoid infringementunder the well known doctrine of equivalents.

What we claim is:

1. A plastic explosive consisting of the following ingredients in thefollowing amounts:

G. 1,2-propylene-glycol dinitrate 37.0 Nitrocellulose 1.3 Methanol 0.4Ammonium nitrate 41.5 Sodium nitrate 18.75 Wood flour 1.0 Chalk 0.05

2. A plastic explosive consisting of the following in gredients in thefollowing amounts:

G. 1,2-propylene-glyco1 dinitrate 37.0 Nitrocellulose 1.4 Ethyl diglycol0.4 Ammonium nitrate 41.3 Sodium nitrate 18.85 Cork flour 1.0 Chalk 0.05

3. An explosive composition having an improved physiological acceptanceand a low sensitivity to impact comprising as its essential ingredients:

(a) 10-95% by weight of an oxygen delivering inorganic salt,

(b) 370% by weight of an explosive oil, said explosive oil beingselected from the group consisting of the dinitrate of 1,2-propyleneglycol, the dinitrate of 1,3-propylene glycol, and mixtures of one ofthese dinitrates with up to 50% by weight of nitroglycerme,

(c) 02-10% by weight of gelatinizing aid and a gelatinizer for saidexplosive oil,

(d) between 0 and 2% of nitroglycol,

said oxygen-delivering inorganic salt being present in an amount tosubstantially oxygen balance the explosive.

4. An explosive composition according to claim 3 wherein saidgelatinizer is nitrocellulose.

5. An explosive composition according to claim 3 wherein saidoxygen-delivering inorganic salt is selected from the group consistingof (a) nitrates of ammonium, alkali metals and alkaline earth metals,(b) perchlorates of ammonium, alkali metals and alkaline earth metalsand (c) chlorates of alkali metals and alkaline earth metals.

References Cited by the Examiner UNITED STATES PATENTS 1,213,369 1/17Hibbert 149104 1,307,033 6/19 Barab 149-104 1,485,003 2/24 Woodbury14947 X 1,637,726 8/27 Bergeim 14947 X 1,640,712 8/27 Moran 149951,879,064 9/ 32 Bryan 149104 2,481,795 9/49 Taylor et a1. 149472,768,073 10/56 Davidson 14948 'X CARL D. QUARFORTH, Primary Examiner.RUEBEN EPSTEIN, Examiner.

3. AN EXPLOSIVE COMPOSITION HAVING AN IMPROVED PHYSIOLOGICAL ACCEPTANCEAND A LOW SENSITIVITY TO IMPACT COMPRISING AS ITS ESSENTIAL INGREDIENTS:(A) 10-95% BY WEIGHT OF AN OXYGEN DELIVERING INORGANIC SALT, (B) 3-70%BY WEIGHT OF AN EXPLOSIVE OIL, SAID EXPLOSIVE OIL BEING SELECTED FROMTHE GROUP CONSISTING OF THE DINITRATE OF 1,2-PROPYLENE GLYCOL, THEDINITRATE OF 1,3-PROPYLENE GLYCOL, AND MIXTURES OF ONE OF THESEDINITRATES WITH UP TO 50% BY WEIGHT OF NITROGLYCERINE, (C) 0.2-10% BYWEIGHT OF GELATINIZING AID AND A GELATINIZER FOR SAID EXPLOSIVE OIL, (D)BETWEEN 0 AND 2% OF NITROGLYCOL, SAID OXYGEN-DELIVERING INORGANIC SALTBEING PRESENT IN AN AMOUNT TO SUBSTANTIALLY OXYGEN BALANCE THEEXPLOSIVE.